Casting machine



March 23, 1937., L. FROMMER ET AL CASTING MACHINE I Filed Feb. 23, 1935 2 Sheets-Sheet 1 Patented Mar. 23, 1937 UNITED? STATES R'A TEl ilf OFFICE oAs'r NG Leopold Frommer, Berlin-Zehlendorf, Germany,

and Josef Polak, Prague,. Czechoslovakia, assignors, by mesne assignments, to the firm Transforma Aktiengesellschaft, Vaduz, Liechtenstein Application February '23, 193d, Serial No. 658,048

In Germany January 19, 1933 a 1 Claim (o1. 22-458) The machines for casting under pressure of this type, which are especially employed for working metals possessing a high melting point, the liquid or pasty metal to be pressed must, on account of the strong cooling effect of the moulds, be filledinto the press chamber only directly before the shot, and after the shot the residue from pressing which has remained in the press chamber and solidified in the meantime must be completely removed from the press chamber. The press chamber must therefore be so arranged that it can be opened or rendered accessible at every operation for filling and for removing the residue from pressing.

Machines for casting under pressure of this type have been carried out already, in which the press chamber is partly arranged in the aggregate containing the mould and partly carried out as an independentpart separate of the casting mould. I a 4 In the constructions of the first mentioned kind the press chamber in the mould half is accommodated as a cavity open towards the separating gap so that by the closing of the mould this i chamber is closed by the other half of the mould and liberated by the opening of the mould. These constructions prevent the inconveniences that the mould can be closed only after the charging of the press chamber (so that the metal which has been filled in is exposed to cooling bythe walls for a comparatively long time), and that the forces exerted by the press plunger (especially also theconsiderable shocks in the mass occur-' ring at the end of the stroke) are transmitted 40 directly upon. the movable mould half, so that they havethe tendency to cause-bursting of the mould.

These inconveniences are avoided in those con- I structions, in which the press chamber is carried 5 out as a separatepart, closed in itself, which is connected withthe mould (situated-either at the side or above or below the press chamber) onlyby a channel (the ingate aperture). In all such constructions the press chamber must have a releasable closure, which during the charging of the mould remains in the closing position and in terrupts the pressures exerted by the press plung er but is opened after the termination of the' of the piston; All these constructions possess the inconvenience that the sliding and packing faces, of the. perfect condition of which the usefulness for service'depends, are exposed to direct contact with the metal to be pressed and therefore are subjected to extremely unfavorable thermical and mechanical stresses so that they soon become damaged. 1

A further inconvenience of this manner of construction consists in that the closure must bear absolutely tightly uponthe seating surface of the press chamber as otherwise, if even the tiniest gap remains open, 'metal would without fail pen-.

etrate through the same under the action of the high pressing'pressure and the burr formed therel5 by would prevent the 'correct working of the slide.

An absolutely tight closing of the press chamber has, however, the result that all the 'air in the press chamber will be forced by the forward moving piston into the mould and be dammed up therein, whereby the enclosing of air in the casting material will be favored) In the machine according to the the ingate channel leading tothe casting meuld, isforced back at the beginning" of the pressure stroke by the press plunger until the ingate channel is liberated," then during the period of mould charging immovably held by an abutment (shiftable perpendicularly to the cylinder axis) and then moved completely out of the press chamber at thetennination of the pressing stroke after withdrawing of the abutment.

This arrangement possesses, in comparison with the above mentioned arrangements, the advantage that the sliding andseating'surfaces of the shutting .oii piston do not come into touch tions. This necessitates on the one hand acertain complicating of the actuating means, and

on the other hand does not allow of employing other but cylindrical (particularly conical) seating surfaces," which in many instances are very desirable.

The present invention differs from what is known in that the closing of the charging-or German Batent 539,817 an axially shiftable plunger serves for shutting ofi the pressure chamber; whichpiston in the charging position of the machine covers ejecting aperture of the press chamber is effected by an element which is at standstill during the whole pressing stroke, the seating surface of whichis shaped rotation-symmetrically relative "'-l-"== to the axis of the press chamber (preferably as cylindrical 'o'r "conical wall). and the removing of which during the opening of the'press chamber takes place in axial direction (or, in other but Figs. 1 and 2 show the diagram'of a machine for casting under pressure with conical closure in two. working positions, 7

Figs. 3 and- 4 diagrams of two other possible 10 forms of construction with cylindrical seating surface and plane circularring seating during the recharging of the mould.

In all figures designates: -A the cylindrical surface I press-chamber, B the press" plunger, C the press c 1 chamber closure, D the charging scoop for charging the press chamber, E the connecting channel between press chamber and hollow mould, F the immovable mould half, G the movable mould half, H the hollow mould,.J the ejecting device.

20 From thedrawings can be clearly seen in which manner the cycle-of a machine carried cut according to,th'e inventiontakes place; After the mould has been closed, the press plunger B is brought into its initial position and .metal is 25 charged .into the press chamber from above, the metalbeing taken by means of a scoop or ladle D from a melting vessel separate from the machine (not indicated in. the figures) (Fig. 1). The.

closing 'piece is then brought into the closing 30 position, in which it is securely held as upper closure of the press chamber during the whole period of the pressing stroke (Figs. 2 to '4). The press'plunger is then moved upwards, the metal being forced into the mould. The closure C is 35 then opened again whereupon the residue from pressing can be removed from the press chamber and-after the opening of the mould-the casting from the latter. i The examples illustrate the advantages of the 40 constructions carriedout according to the invention The press chamber closure, which in any case is particularly strongly stressed. thermically and mechanically, is,;owing to the rotationsymmetrical shapeof the seating surface, very 45 easy to produce in workshop technical respect.

The seating surfaces are-protected against the direct action of the metal to be pressed. By conical'or sphericalshape of the seating su rfaces it can be obtained that a metal burr 'penef 50 trating into thepacking joint cannot give cause for theseizingofthe closure. As regards construction machines according to the invention can be carried out in very various manners. For example the seating surface of v (Fig.3), conical ,,(Flgs. 1, 2), spherical or even plaiie (Fig. 4). The openingand closing movement of the closure piecefC can (if the seating surface is conical (spherical or plane) be either a straight linemovement (Fig. 3) or a folding movement gs. 1, 2) or a combined movement. The control ng and actuating of this movement can be effected by control, means and power 1.-means of most diff'erentkind. .Either such conthe press chamber closure can be: cylindrical trol means can be employed, which as for infrom pressing is completely liberated by removing.

press chamber isv effected by a closure piece with preferably rotation-symmetrical seating surof the mould is'tran'sferred from this closing posiaxis of the chamber.

her in that the cylinder side actuating the closing movement is shutofl from the'conduit for water under pressure, as in this case the enclosed quantity of water owing to its incompressibility presents yielding of the hydraulic piston and thereby of the closure piece.

The whole arrangement, serving for guiding and actuating the closure element, may further be arranged in such a manner on the machine frame, that during the opening it can be 'slewed away from the press chamber so that the closure piece C need carry out only a very short stroke and the press chamber is ,quite freely accessible in the open position.

The ingatechannel E leading to the mould can either interrupt the wall of the press chambar or be arranged at the end of the press chamber as agutter extending transversely across the seating surface. The first mentioned arrangement is always advisable if the ingate channel A extends through the one mould half (Figs. 1 to 3). In this instance the residue from pressing must be shorn off by the ingate pin after the complete filling of the mould in order that it may be ejected from the press chamber and that the. ingate pin together with the casting can be r'emoved from the front mould plate during the opening of the mould. In this case the casting together with the ingate metal and the residue the closure piece C and opening of the mould so that all these parts together can be ejected.

, Evidently the possibilities of carrying out the invention are not limited to those indicated in the-above specification and illustrated in the drawings. Machines for casting under pressure according to the invention may-be constructed in many other manners, as the essential feature of the invention consists in that the closing of the faces, which closure piece during the whole pressing stroke stands immovably in the closing position but after the termination of the recharging tion into an opening position liberating the press chamber "and by a movement. the direction of which "coincides at least at the beginning with the direction of the'pre'ss chamber axis.

We claim: I

A machine for casting metals under pressure, comprising an independent press chamber havingat one end a detachable closure piece, a casting mould separate from the press chamber and its' closure piece, a piston for supplying the material to be pressed to the casing mould under pressure from the press chamber, said closure piece bein'gstationary during the pressure stroke,

- means for opening and closing the press chamher by movement of the closure piece, the direction of said movement adjacent the closing position approximately coinciding with the direction of the press chamber axis and means whereby the closure piece follows a swinging movement about an axis at right angles to the LEOPOLD F ROMMER. JOSEF POLAK. 

